1. Field of the Invention
The present invention relates to an image forming apparatus including a copying machine, a facsimile machine, or a printer.
2. Description of the Related Art
Some conventional image forming apparatuses are capable of printing halftone images with sharp image quality. One such image forming apparatus is disclosed in Japanese Patent Laid-Open No. 09-325619. A toner image is formed on a photoconductive body. The toner image is transferred by a transfer roller onto print paper. The photoconductive body and the transfer roller rotate in contact with each other such that a nip is formed between the photoconductive body and the transfer roller. A nip-adjusting mechanism adjusts the size of the nip in accordance with the transfer mode.
Such a conventional apparatus suffers from the problem in that image noise is apt to occur in the mid levels of halftone. In other words, the image noise appears in a direction substantially perpendicular to a direction in which the print paper is advanced.